. . .
If you so strongly believe this, then fly an N1K and DA someone competent in the aircraft you listed (Spit, F4U-1c, etc.). Your N1K will get stomped.
The N1K's only advantage is it's guns. Turn performance is decent, but it's outmaneuvered by LA's, Spit 8/16's, and it's combined climb+turn performance is worse than a Spit 9, Yak 3/9's. It's slower than Typhoons, P-51's, D9's and 152's, 109G14/K4. Its only advantage is how much hitting power it can bring. It's an aircraft suited for very aggressive players that typically come into fights with extra altitude/airspeed. Co-alt at cruise speed, it's fairly average, and its performance only gets worse as you climb above 12k (performance drops off significantly there).
It is very much the Japanese version of the Typhoon, with all of the performance it implies. With alt and E on the opponent, they seem great. Take that away and force a co-alt fight, and you'll quickly find how poorly they perform in general.
Watch someone like 2cmex who flies it, and you'll notice from the moment he engages, his overall flight path is almost entirely downhill. It doesn't have the energy on its own to be a threat. Meet one co-alt and you'll find they're hardly the monster you make them out to be.
In this situation, it seems your real problem isn't the N1K, it's a lack of SA combined with N1K's who are taking advantage of you being low and slow.